المقياس الدولي للأحداث النووية والإشعاعية (International Nuclear and Radiological Event Scale واختصاره INES) قـُدِّم في 1990 من الوكالة الدولية للطاقة الذرية (IAEA) لتمكن ابلاغ سريع بالمعلومات السلامة الهامة في حالة حادث نووي.

والمقصود حتىقد يكون المقياس لوغاريتمي، مشابه لمقياس ريختر الذي كان يستخدم لوصف القوة المقارنة للزلازال. جميع مستوى في المقياس يمثل حوالي عشر أضعاف المستوى السابق له. مقارنة بالزلازل، حيث يمكن تقييم شدة الحدث كميا، مستوى شدة كارثة من خلق الإنسان، مثل الحادث النووي، is more subject to interpretation. بسبب صعوبة التفسير، فإن المقياس الدولي للأحداث النووية يتم تعيينه بعد حدوث الحدث مباشرة. ولذلك، فإن قدرة المقياس محدودة للغاية بالمساعدة في نشر الإغاثة من الكوارث.

Commonly, the organisation where the nuclear incident occurs assigns a first provisional INES rating to an incident, after it is being reviewed and possibly revised by the designated national radiation authority.

A number of criteria and indicators are defined to assure coherent reporting of nuclear events by different official authorities. يوجدسبعة مستويات في المقياس الدولي للأحداث النووية؛ ثلاثة مستوياتللأحداث و4 مستويات-حوادث. ويوجد أيضا المستوى 0.

التفاصيل

The level on the scale is determined by the highest of three scores: off-site effects, on-site effects, and defence in depth degradation.

المستوى 7: حادث عظيم

التأثير على البيئة والإنسان

Major release of radio­active ­material with widespread health and environmental effects r­equiring implementation of planned and extended ­countermeasures

الحادثة الوحيدة:

• كارثة تشرنوبل، 26 أبريل 1986. سبب ازدياد الطاقة أثناء اجراء إختبار، حادث عظيم، إلى إنفجار بخاري قوي وحريق إدى إلى إنبعاث a significant fraction of core material إلى البيئة، مما تسبب في وفاة 56 إنسان كما قدر عدد المصابين بالسرطان بأكثر من مليون إنسان ممن تعرضوا لجرعات متحملة من الإشعاعات وفقدان مساحات سكنية شاسعة. وكان هذا هوالحادث الوحيد الذي سقط من المستوى 7.

المستوى 6: حادث خطير

التأثير على البيئة والإنسان

Significant release of radioactive material likely to require implementation of planned countermeasures.

مثال

• Kyshtym disaster في ماياك، الاتحاد السوڤيتي، 29 سبتمبر 1957. إنهيار نظام التبريد في منشأة معالجة نفايات نووية عسكرية أدى إلى ان at a military nuclear waste reprocessing facility caused a steam explosion that released 70–80 tons of highly radioactive material into the environment. Impact on local population is not fully known.

المستوى 5: حادث ذوعواقب أوسع

Impact on People and Environment

Limited release of radioactive ­material likely to require i­mplementation of some planned­ countermeasures.

Several deaths from ­radiation.

مثال

• Windscale fire (United Kingdom),عشرة October 1957. Annealing of graphite moderator at a military air-cooled reactor caused the graphite and the metallic uranium fuel to catch fire, releasing radioactive pile material as dust into the environment.

Impact on Radiological Barriers and Control

Severe damage to reactor core.

Release of large quantities of radioactive material within an installation with a high probability of significant public exposure. This could arise from a major criticality accident or fire.

Example: Three Mile Island accident (Harrisburg, United States), 28 March 1979. A combination of design and operator errors caused a gradual loss of coolant, leading to a partial meltdown. Radioactive gases were released into the atmosphere.

أمثلة أخرى:

• First Chalk River Accident Chalk River, Ontario, Canada, 12 December 1952. Reactor core damaged.
• Goiânia accident (البرازيل), 13 September 1987. An unsecured caesium chloride radiation source left in an abandoned hospital was recovered by scavenger thieves unaware of its nature and sold at a scrapyard. 249 people were contaminated and أربعة died.

المستوى 4: حادث ذوعواقب محلية

Impact on People and the Environment

Minor release of radioactive material unlikely to result in implementation of planned countermeasures other than local food controls.

At least one death from radiation.

Impact on Radiological Barriers and Control

Fuel melt or damage to fuel ­resulting in more than 0.1% release of core inventory.

Release of significant quantities of radioactive material within an installation with a high ­probability of significant public exposure.

الأمثلة:

• Sellafield (United Kingdom) –خمسة incidents 1955 to 1979
• SL-1 Experimental Power Station (United States) – 1961, reactor reached prompt criticality, killing three operators.
• Saint-Laurent Nuclear Power Plant (France) – 1980, partial core meltdown.
• بوينس آيرس (الأرجنتين) – 1983, criticality accident during fuel rod rearrangement killed one operator and injured 2 others.
• Jaslovské Bohunice (Czechoslovakia) – 1977, contamination of reactor building.
• Tokaimura nuclear accident (Japan) – 1999, three inexperienced operators at a reprocessing facility caused a criticality accident; two of them died.
• Fukushima I Nuclear Power Plant (Japan) – 2011, reactor shutdown after the 2011 Sendai earthquake and tsunami, failure of emergency cooling caused an explosion.

المستوى 3: وقع خطير

Impact on People and Environment

Exposure in excess of ten times the statutory annual limit for workers.

Non-lethal deterministic health effect (e.g., burns) from radiation.

Impact on Radiological Barriers and Control

Exposure rates of more than 1 Sv/h in an operating area.

Severe contamination in an area not expected by design, with a low probability of ­significant public exposure.

Impact on Defence-in-Depth

Near accident at a nuclear power plant with no safety provisions remaining.

Lost or stolen highly radioactive sealed source.

Misdelivered highly radioactive sealed source without adequate procedures in place to handle it.

الأمثلة:

• THORP plant Sellafield (United Kingdom) – 2005.
• Paks Nuclear Power Plant (fuel rod damage in cleaning tank) (Hungary) – 2003.
• Vandellos Nuclear Power Plant, Spain (A large fire destroyed many control systems, but the reactor could be stopped) – 1989.

المستوى 2: حدث

Impact on People and Environment

Exposure of a member of the public in excess ofعشرة mSv.

Exposure of a worker in excess of the statutory annual limits.

Impact on Radiological Barriers and Control

Radiation levels in an operating area of more than 50 mSv/h.

Significant contamination within the facility into an area not expected by design.

Impact on Defence-in-Depth

Significant failures in safety ­provisions but with no actual ­consequences.

Found highly radioactive sealed orphan source, device or transport package with safety provisions intact.

Inadequate packaging of a highly radioactive sealed source.

الأمثلة:

• Ascó Nuclear Power Plant, (Catalonia, Spain) April 2008; radioactive contamination
• Forsmark Nuclear Power Plant (Sweden); backup generator failure.

المستوى 1: Anomaly

Impact on Defence-in-Depth

Overexposure of a member of the public in excess of statutory ­annual limits.

Minor problems with safety components with significant defence-in-depth remaining.

Low activity lost or stolen radioactive source, device or transport package.

(Arrangements for reporting minor events to the public differ from country to country. It is difficult to ensure precise consistency in rating events between INES Level-1 and Below scale/Level-0)

أمثلة:

• Gravelines (Nord, France),ثمانية August 2009; during the annual fuel bundle exchange in reactor #1, a fuel bundle snagged on to the internal structure. Operations were stopped, the reactor building was evacuated and isolated in accordance with operating procedures.
• TNPC (Drôme, France), July 2008; leak of 6000 litres of water containing 75 kg of Uranium into the environment.

المستوى 0: Deviation

لا أهمية له من حيث السلامة.

أمثلة:

• 4 June 2008: Krško, Slovenia: Leakage from the primary cooling circuit.
• 17 December 2006, Atucha, Argentina: Reactor shutdown due to Tritium increase in reactor compartment .
• 13 February 2006: Fire in Nuclear Waste Volume Reduction Facilities of the Japanese Atomic Energy Agency (JAEA) in Tokaimura .

خارج المقياس

There are also events of no safety relevance, characterized as "out of scale".

أمثلة:

• 17 November 2002, Natural Uranium Oxide Fuel Plant at the Nuclear Fuel Complex في حيدرأباد، الهند: A chemical explosion at a fuel fabrication facility
• 4 November 1999: H.B. Robinson, United States: A Tornado sighting within the protected area of the NPP.
• 15 April 1999: San Onofre, United States: Discovery of suspicious item in nuclear power plantنطقب:Dead

انظر أيضا

الهامش

• INES Scale – International Nuclear and Radiological Event ScalePDF

وصلات خارجية

• Nuclear Events Web-based System (NEWS), IAEA
• International Nuclear Event Scale factsheet, IAEA
• International Nuclear Event Scale, User's manual, IAEA, 2001